Malfunction of the lacrimal glands causes aqueous deficient dry eye. There is presently no treatment for lacrimal gland disease and progress towards development of effective therapy requires a thorough understanding of lacrimal function. The lacrimal gland is a tubulo-acinar gland with both acinar cells and ducts. The accessory lacrimal glands found in the palpebral and tarsal conjunctiva also produce aqueous tears. Little is known about the function of the lacrimal gland duct epithelium or accessory glands because of their small size and inaccessibility which makes it difficult to separate them from surrounding tissue. The purpose of the proposed study is to explore the feasibility of using laser capture microdissection to isolate and analyze these cell types. The specific aims of the project are to: 1) Sample rat exorbital lacrimal gland duct epithelial cells and accessory lacrimal gland acinar cells by laser capture microdissection, 2) compare gene expression among exorbital gland duct cells, exorbital gland acinar cells and accessory gland cells by gene microarray analysis, 3) identify selected genes that are differentially expressed in these cell types. The results of this study are expected to form the basis for further studies that will clarify the role of duct cells in the secretion and modification of lacrimal fluid and also lead to a better understanding of the role of accessory glands as compared to the main lacrimal gland in tear secretion.